Machine for forming gears



H. PELPHREY 2,348,845

MACHINE FOR FORMING GEARS Filed Oct. 6, 1942 v s Sheets-Sheet 1 INVENTOR fidrr g Eel 52%;

A TTORNE K Filed Oct. 6, 1942 3 Sheets-Sheet 2 E. w W H May 16, 1944. H, PELPHREY 2,348,845

MACHINE FOR FORMING GEARS Filed Oct. 6, 1942 3 Sheets-Sheet 3 I NVEN TOR H4273; PsZ /"egy.

A TTOR NE Y Patete ay 1, 144

FFICE MACHINE FOR. FORMING GE i Harry Pelphrey, Detroit, Mich., assignor to chi gan Tool Company, Detroit, Micln, a corporw tion of Delaware Application October 6, 1942, Serial No. 460,976

7 Claims.

The present invention relates to improvements in machines for forming worms of the globoidal r Hindley type.

The primary object of the present invention is to provide improvements in machines of the type mentioned in which relief is provided on the thread flanks of worms of the globoidal or Hindley ype.

Other objects of the invention will become apparent from the following specification, the drawings relating thereto, and from the claims hereinafter set forth.

In the drawings, in which like numerals are used to designate like parts in the several views throughout:

Figure 1 is a perspective view of a machine having the thread forming means of the present invention associated therewith;

Fig. 2 is a top plan view ofthe thread forming means of the present invention;

Fig. 3 is a cross-sectional view taken substantially along the line 3-3 of Fig. 2;

Fig. 4 is a cross-sectional view taken substantially along the line i--t of Fig. 2; and

Fig. 5 is a cross-sectional view taken substantially along the iine 5-5 of Fig. 2.

The structure of the present invention is particularly adapted for providin the relief in the thread flanks of the worms disclosed and claimed in Scott Patent No. 2,279,414 issued April 14, 1942.

In such patent the worm, provided with the end relief on the threads thereof, is disclosed and claimed and the character and importance of such relief is described in detail. In general, the relief provides a modification of the worm thread in that the flanks of the thread adjacent the ends are relieved so that'the load may be transmitted to the engaged tooth much more gradually and smoothly. The extent of the relief is gradually reduced from the ends or flanks of the thread toward the center of the worm.

The cutting means of the present invention is mounted upon the vertical spindle of the automatic machine disclosed in Pclphrey application, Serial No, 435,649, filed March 21, 1942. The worm is formed on the machine there disclosed by employing the cutter there disclosed on the vertical spindle. In the machine of the present invention, the cutting means of the present invention then replaces the cutter employed in the machine of the Pelphrey application referred to. The worm is disposed on the horizontal spindle and the cutter of the present invention is operated by the machine described in detail in the application reierred to to provide the end relief. The cutter may be positioned at the limit of in-feed and it is only necessary to provide the side feed of the application to provide" the relief on the worm threads. The operating elements of the machine of the present inventionfor operating the vertical and horizontal spindles in synchronism are the same as in the application referred to and reference may be had to such application for a detailed description of such operating means.

Referring to the drawings, an automatically controlled machine is illustrated which comprises a base til, which serves to mount a vertical spindle having a rotatable work table l2 fixed thereto for rotation therewith. The cutting means of the present invention is generally indicated at It and is mounted to table 52 for rotation therewith.

The worm to be formed is indicated at [6 and is mounted to a slide 68 which is mounted on horizontal, parallel ways, formed on the top surface of the base Ill so that such slide is slidable on parallel lines toward and from thework table l2. The side I8 serves to mount a horizontal work spindle 20 upon which is mountedthe worm l6. One end of the worm is suhportcdfi the head stock 20 and the other end is mounted on a removable tail stock 22.

The cutting means it includes a circular plate 24 which rests upon the table 12 and is secured thereto by means of suitable bolts 26, located at spaced intervals therearound. Another plate member 28 is supported upon the top surface of the plate 24 and is mounted. for limited relative rotation with respect thereto. Th plate members 24 and 28 are provided with axial bores 30 and 32, respectively, therethrough. A headed pivot pin 34 having an upper portion 36 of reduced diameteris received through the aligned apertures .30 and 32 and projects slightly upwardly above adapted to bear against the top surface of the bearing member 40; The screw 46 may be adjusted to take up wear between the bearings 38 and 4|).

The platemember 24 is formed with diametrically opposed bosses 48 which are disposed under diametrically opposed bosses 50 formed on the member 28. L-shaped bearing members 52 are secured t0 the bosses 50. by means of screws 54 and have portions which extend under the bosses 48 and slidably engage the under surfaces thereof so as to permit rotative movement between the members 24 and 28 but to hold the member 28 against the top surface of member 24.

Another plate member 58 is disposed on the top surface of the plate member 28 and is provided with an axial aperture 68 therethrough which is adapted to bear against the upper peripheral edge of the bearing member 38. The plate member 58 may be rotatively adjusted in its position on the member 28 and is secured thereto by means of a clamping ring 62 which has an inturned flange which engages an annular shoulder on the member 58 to clamp the member 58 in its adjusted position with respect to the member 28. Screws 64 are provided at suitable spaced intervals around the ring 62 which are adapted to be received within tapped openings in the member 28 for tightening the clamp 62 and securing the plate 58 in its adjusted position.

Another mounting plate 66 is slidably disposed on the member 58 and is formed with a key way 68 upon the under surface thereof. Such key way 68 is adapted to be superimposed above key ways I8 formed in the member 58 on opposite sides of the central aperture 68 and extending diametrically therefrom. Keys 12 are received within the key ways 68 and I8, so that the mounting plate 66 may slide relative to the member 58. The member 86 may be fixed in position on the member 58 by means of cap screws I4, which pass through elongated slots provided in the members 86 and which are received within tapped openings in the member 58.

The supporting member 88 has an integral upstanding block E8 on the top surface thereof. The upper surface of such block is formed with parallel sides M which provide guideways for the base 88 of a cutter holding member 82. Member 18 is formed with a T-slot 84 transversely thereof which is adapted to receive the heads of screws passed through the base 88 and provided with nuts 86 on the upper ends thereof for the purpose of adjustably fixing the tool holder 82 in its proper position along the member E8. The tool holder 32 is formed with a cyiindrical bore 88 extending horizontally therethrough which receives a cylindrical tool holding member 88 therein. Such member 88 snugly fits within the bore 88 and is retained in predetermined angular position by means of suitable set screws. The rotary tool holding member 98 has a tool receiving slot 92 therein, one of the side walls of which lies on a plane through the axis of the tool holding member and intersecting the top wall of the slot at right angles at this axis. A cutting tool 94, having a cutting edge 86, is retained in position in the slot 82 by means of cooperating wedges.

The holder 82 is fixed in position on the member I6 so that the cutting edge 86 of the tool 94 is disposed tangent to the base circle of the worm to be formed with the body of the tool 94 disposed on the inner side of the base circle, to the right of the central position viewing Fig. 2. The correct distance for setting the tool holder so that the cutting edge 96 is tangent to the base circle is determined by a gage block 95, of proper size depending upon the base circle, which is disposed between a center block 91 mounted on member I6 and a stop block 99 mounted in a predetermined position on holder 82.

The relative movement between the members 24 and 28 is imparted to these members by means of a bell crank member I8I, which is fulcrumed to a pivot pin I82. The pivot pin I82 is received within an aperture I84 formed in the member 24 adjacent the periphery thereof. The member IN is formed with an inwardly disposed rectangular aperture I86 in the body thereof adjacent the fulcrum. The member 28 has 2. depending pin I88 received through an aperture II8 formed therein, and the lower end of such pin I88 is received within an aperture formed in member I I2, such aperture being complementary in shape and size to the member I88. The member II2 is rectangular in shape and is slidably received within the recess I86. The member II2 is of such a size with respect to the recess I86 that it may move therein. The body portion of the member I8I, having recess I88 formed therein, and the member II2 are received within a recess provided in the top surface of the member 24, so that the member II2 is slidably supported on the top surface of the member 24 and may move within the recess formed therein. One of the arms of the bell crank member I82 has an ad- ,iustable set screw I I6 passing therethrough. The extent that the set screw II6 projects through the arm may be adjustably variedand the inner end of the set screw is adapted to bear against the hardened head of a stop screw H8 which is set in member 24.

The other arm of the bell crank I8l has a roller follower I28 rotatably mounted thereon, and such roller follower is adapted to engage the cam surfaces I22 and I24 of cam plates I26 and I28, respectively. The cam plates I26 and I28 are pivotally supported upon the top surfaces of blocks I38 by central pivot pins I3I. The cam plate may be adjustably fixed to blocks I38 about'the pivots I3I by set screws I32 which pass through arcuate slots I34, having the pivots I3I as centers, and are received in tapped openings in members I38. The members I38 rest upon supporting plates I33 and are adjustably fixed thereto by set screws I35 which pass through elongated slots formed in end flanges on members I38. The plates'l33 are adjustably mounted on the base I8 by means of set screws which pass through elongated slots I31 formed therein. The slots in the various members are so positioned that the cam plates can be adjusted in practically any direction with respect to the table. The cam plates I26 and I28 may thus be adjustably fixed with respect to the path of movement of the follower I28.

The member 28 is urged in a counterclockwise direction, (viewing Fig. 2) by means of a com-' pression spring I36, which is received within a bare I38 provided in the member 24. The spring acts against 9. depending pin I48, which is fixedto the plate 28 and depends within an enlarged aperture I42 provided in the member 24. with the spring urging the member 28 to move in a counterclockwise direction with respect to the member 24 (viewing Figure 2), the pin I88 acts on one side of the recess I86, through the block- II2, to urge the follower I28 outwardly or in a clockwise direction (viewing Fig. 2). The 10!- lower may move outwardly until it engages one of the cam surfaces I22 or I24, or until the stop screw H6 engages the stop II8. Except for the times when the follower I28 is engaging the cam track I22 or I24, the set screw II8 engages the stop I I8, and this may be termed the normal position of the member 28 with respect to the mem ber 24. With the cutter properly positioned on the base circle of the worm, and with the cutter table positioned onthe proper center distance, ii the cutter were then actuated without using thecam plates I26. and 128, the cutter would follow the same contour as that on theformed worm. This movement ismodifled in order. to obtain the end relief desired by- .the action of the cam plateslZBand-IZBL With the cutterpositionedas described above, and using thecam plates, as the; cutter 96v approaches'the entering side of the worm, the follower l flil is in substantially the position shown in Fig. 2. Roller lzilmiszthen following the cam surface I22, and the action through the bell crank It! is to move-the plate 28 clockwise with respect to the plate 24. This positions the cutting edge 96 to take .the deepest cut on the entering end or the worm thread and on the lefthand side of the thread. The cutter and the table 82 are moving in a clockwise direction to make the out. As the follower E29 moves along the cam 22, such cam is of such a shape that the plate 28 moves in a counterclockwise direction relative to the member 25, so that the cutting edge at is retracted from its depth of out. In this way, the amount of relief is gradually reduced toward the center of the worm. When the tollower l2li reaches the space between cam plates M6 and 528, the cutting edge 96 is in its normal position with respect to the plate 24, so that no cutting action takes place on the center portion of the worm. When the follower I28 engages the cam edge EM, a clockwise relative movement is imparted to the member 28, which causes the cutting edge 96 to begin taking a cut in the worm thread, and such cut is progres sively increased until the cutting tool 95 leaves the leaving end of the thread. It will be appreciated that the amount and contour of the relief may be varied by adjusting the cam plates or by changing the shape of the cam edges.

With the set-up above described, it will be appreciated that only one side of the thread is relieved. To relieve the other side of the thread, a cutter holder the same as the cutter holder 82 is provided which is of the opposite hand. The cutting tool is also of the opposite hand, and is positioned on the opposite side of the base circle, from that described above. The spindle M2 would be driven in a reverse direction from that described above, and the bell crank itl would be reversed in its position, so that the follower B29 would follow the direction of rotation and engage the cam 628 first and then the cam ltfi, so that the relative movement would take effect when the cutter was in the proper position. The plate 58 may be adjustably fixed to the member 28 by releasing the clamp 62, turning the plate 58 to its proper position, and reclamping the rings 52. The cutting would then be repeated to provide the relief on the other side of the thread.

What is claimed is:

1. Apparatus for relieving the flanks of the thread of a worm of the globoidal type comprising, in combination, means for rotating a worm to be machined, means carrying a cutting tool adapted to pass through the thread of the worm, said last named means including a rotatable table and a tool supporting member mounted on said table for limited rotative movement with respect thereto about the axis of rotation of said table, means causing such relative movement, and means to effect timed rotation of said table with respect to the rotation of the worm.

2. Apparatus for relieving the flanks of the said last-named means including. a rotatable table and atool supporting membermountedon, said table forv limited.rotative-movement with-respect thereto about the axis of rotation of said table,

means causing such irelative; rotative movement at the flanksofithe worm,-.and':means,to.-,efect :timed rotation.- of said..table:.with1;resp ect as the rotation of the worm. Y 2

; 3.. 1 Apparatus. ltor; relievi, thread of. a wormoi the.globoidaltype;comprising, in,.combination,-. means {or rotating a worm to be machined, means carrying a cutting tool adaptedto pass-through the thread; of the worm, said last named means including ,arotatable table,

a tool supporting member-mounted onsaid table -forlimite,d rotative movementwith respect thereto about-the axis ofrotation-of said tab1e,.means mounting saidcutting ..tool with the-cutting edge thereof. tangent-.to-the base.circle .,of,;the'worm, means causing such relativerotative movement,

and means to, efiecttimecl rotation .of said table withrespect-to therotation of the worm.

. .4. Apparatus for; relieving the, flanks of the thread of a wormofthegloboidal- ,typecomp-rising, in combination,..means for rotating-a worm to be machined, means carrying a cutting tool adapted to pass through the. thread of the worm, said last named means including a rotatable table and a tool supporting member mounted on said table for limited rotative movement with respect thereto about the axis of rotation of said table, cam means causing such relative rotative movement, and means to efiect timed rotation of said table with respect to the rotation of the worm.

5. Apparatus for relieving the flanks of the thread or a worm of the globoidal type comprising, in combination, means for rotating a worm to be machined, means carrying a cutting tool adapted to pass through the thread of the worm, said last named means including a rotatable table and a tool supporting member mounted on said table for limited rotative movement with respect thereto about the axis of rotation of said table, a

a pair of spaced cams mounted adjacent said table,

a cam follower member operatively connected to said supporting member and adapted to engage said cams for causing such relative rotation, and means to effect timed rotation of said table with respect to the rotation of the worm.

6. Apparatus for relieving the flanks of the thread of a worm of the globoidal type comprising, in combination, means for rotating a worm to be machined, means carryln a cutting tool adapted to pass through the thread of the worm, said last named means including a rotatable table and a tool supporting member mounted on said table for limited rotative movement ,with respect thereto about the axis of rotation of said table, a pair of spaced cams mounted adjacent said table, a cam follower member operatively connected to said supporting member to engage said cams for causing such relative rotation, said cams being so I ing, in combination, means for rotating a worm to be machined, means carrying a cutting tool adapted to pass through the thread of the worm, said last named means including a rotatable table and a tool supporting member mounted on said table for limited rotative movement with respect thereto about the axis of rotation of said table, resilient means urging said table and said supporting member to their normal position with respect to each other, means acting against said resilient means during portions only of the travel of said table causing such relative movement, and means to eifect timed rotation of said table with respect to the rotation of the worm.

HARRY PELPHREY. 

